The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Diesel engines typically have higher efficiency than gasoline engines due to an increased compression ratio and a higher energy density of diesel fuel. A diesel combustion cycle produces particulates that are typically filtered from diesel exhaust gas by a particulate filter (PF) that is disposed in the exhaust stream. Over time, the PF becomes full and the trapped diesel particulates must be removed. During regeneration, the diesel particulates are burned within the PF.
Conventional regeneration methods inject fuel into the exhaust stream after the main combustion event. The post-combustion injected fuel is combusted over one or more catalysts placed in the exhaust stream. The heat released during the fuel combustion on the catalysts increases the exhaust temperature, which burns the trapped soot particles in the PF. This approach, however, can result in higher temperature excursions than desired, which can be detrimental to exhaust system components including the PF.